Issued yesterday, EPA's final "tailoring" rule determines which polluters will be required to account for their greenhouse gas emissions in Clean Air Act permits when the agency begins to formally regulate the heat-trapping gases next January (Greenwire, May 13).

Emissions from biomass or biogenic sources are treated the same as other sources of greenhouse gases in the final rule, EPA spokeswoman Cathy Milbourn said. "We have not finalized any exemptions from applicability or different applicability thresholds for such sources at this time."

That decision "came as a bit of a surprise to us," said David Tenny, president and CEO of the National Alliance of Forest Owners.

Tenny's organization and other forestry groups had urged EPA to exclude biomass combustion from the requirements, arguing that the process is "carbon neutral."

Paul Noe, vice president for public policy at the American Forest & Paper Association, was one of several representatives from his organization who met last month with White House and EPA officials to push for a biomass exemption in the rule.

"When biomass such as wood is combusted for energy, it releases back into the atmosphere carbon dioxide that the trees had absorbed from the atmosphere during their growth," Noe said. "That is why CO2 emissions from biomass combustion are assigned an emissions factor of zero."

Without an exemption from the tailoring rule, Tenny said, "what you have is an incentive for biomass producers to turn back to fossil fuels," because they offer a more concentrated energy source.

"The question is, what is EPA going to do from here?" Tenny said. "This sends a bit of a chilling message to biomass producers."

EPA also received comments expressing concern that not all biomass combustion should be considered carbon-neutral.

Franz Matzner, a policy analyst for the Natural Resources Defense Council, said EPA's rule must distinguish between biomass that creates carbon pollution and biomass that does not.

"The science around biomass continues to make clear that not all biomass is good from a carbon footprint perspective," Matzner said. "Some sources of biomass can theoretically be carbon-beneficial: for example, taking waste streams from agricultural crops and burning that is most likely going to give you reductions in greenhouse gases compared to fossil fuels.

"On the other side of the fence, chopping down a swath of forest that then gets turned into a parking lot and burning it puts carbon in the atmosphere that's not going to regrow."

While EPA said it lacked sufficient basis to exclude carbon dioxide emissions from biogenic sources in determining permitting applicability at this time, it also said treating biomass combustion differently warrants further exploration.

There is flexibility to apply pollution control requirements to biomass sources in ways that "recognize the inherently lower-emitting characteristics of biomass," Milbourn said, and the agency will take that into account when it issues guidance later this year about what constitutes "best available control technology," or BACT, for specific sources.

EPA said it also plans to seek further comment on addressing biogenic emissions and could take further regulatory action in the future.

Agriculture Secretary Tom Vilsack yesterday welcomed EPA's plans to seek comment on how to address biomass under the Clean Air Act.

"As this process moves forward, USDA is committed to working with EPA to ensure that rules designed to reduce the buildup of greenhouse gases in the atmosphere also encourage the development and utilization of biomass energy resources and avoid unnecessary regulatory impediments and permitting requirements," Vilsack said in a statement.